<!doctype html>
<html>
 <head>
  <meta charset="UTF-8">
  <title></title>
 </head>
 <body>
	<script>
//选做题5
	/*	var a = 0,b = 0;
		for (i = 1;i <= 100;i++){
			if(i%2==0){
				a=a+1/i
			}else{
				a=a-1/i
			}
		}
		console.log(b-a);*/
//选做题6
		for(var i=1000;i<=2000;i++){
			if(i%400==0||i%4==0&&(!(i%100==0))){
				document.write(i);
				document.write("<br>");
			}
		}
	</script>
 </body>
</html>
